Fabrication and Properties of Al-Cr Coatings on the Inner Wall of Steel Pipe by Mechanical Alloying Method

2013 ◽  
Vol 537 ◽  
pp. 279-282 ◽  
Author(s):  
Zhong Qing Tian ◽  
Guo Xing Zhang ◽  
Wei Jiu Huang ◽  
Yu Kai Zhu
Keyword(s):  
Friction Coefficient ◽  
Mechanical Alloying ◽  
Coating Thickness ◽  
High Speed ◽  
Testing Machine ◽  
Steel Pipe ◽  
Interparticle Contact ◽  
Rotating Speed ◽  
Friction Testing ◽  
Cr Coating

Surface coatings; Mechanical alloying; Microstructure; Tribological properties Abstract. The mechanical alloying method process has been innovatively used to prepare Al-Cr coating on the inner wall of steel pipe. The coating thickness was measured from all samples using optical and Scanning Electron Microscope was used to observe the surface microstructure of Al-Cr coating. Microhardness was analyzed by Digital Microhardness Tester. A wear test was performed by high speed reciprocating friction testing machine. The results show that the coating thickness is 20μm and 26μm at the rotating speed of 200 rpm and 300 rpm, respectively. The surface morphology is significantly influenced by the the rotating speed. When the rotating speed was 200 rpm, a heterogeneous coating surface consisting of flattened particles produced by cold welding with less interparticle contact is formed. When the rotating speed was 300 rpm, the coating became denser and a smooth, highly consolidated and dense coating is formed. The hardness of the Al–Cr coating prepared at 200 and 300 rpm are about 250 Hv and 270 Hv. The friction coefficient of the Al–Cr coating prepared at 200 rpm are about 0.37, 0.39 and 0.24 at the frequencies of 3, 4 and 5 Hz. The friction coefficient of the Al-Cr coating prepared at 300 rpm are about 0.3, 0.18 and 0.28 at the frequencies of 3, 4 and 5 Hz.

Fabrication and Properties of Cu-Cr Coatings on the Inner Wall of Steel Pipe by Mechanical Alloying Method

2012 ◽  
Vol 602-604 ◽  
pp. 1663-1666
Author(s):  
Zhong Qing Tian ◽  
Guo Xing Zhang ◽  
Wei Jiu Huang ◽  
Yu Kai Zhu
Keyword(s):  
Friction Coefficient ◽  
Mechanical Alloying ◽  
Coating Thickness ◽  
High Speed ◽  
Testing Machine ◽  
Optical Microscope ◽  
Steel Pipe ◽  
Rotating Speed ◽  
Friction Testing ◽  
Cr Coating

The mechanical alloying method process has been innovatively used to prepare Cu-Cr coating on the inner wall of steel pipe. The effect of the rotating speed on thickness, microhardness and friction coefficient of the Cu-Cr coating was investigated. The coating thickness was measured from all samples using optical microscope. The microhardness was analyzed by Digital Microhardness Tester. The friction coefficient was tested by high speed reciprocating friction testing machine. The results show that the coating thickness is 26, 29 and 31μm at the rotating speed of 200, 250 and 300 rpm. The microhardness of the Cu-Cr coating prepared at 200, 250 and 300 rpm are about 760, 780 and 830 Hv. The friction coefficient of the Cu-Cr coating prepared at 200 rpm are about 0.25, 0.40 and 0.38 at the frequencies of 3, 4 and 5 Hz. The friction coefficient of the Cu-Cr coating prepared at 250 rpm are about 0.30, 0.29 and 0.20 at the frequencies of 3, 4 and 5 Hz. The friction coefficient of the Cu-Cr coating prepared at 300 rpm are about 0.10, 0.13 and 0.09 at the frequencies of 3, 4 and 5 Hz.

Effects of Load and Rotate Speed on the Friction of NBR by 45# Steel in Crude Oil Medium

2011 ◽  
Vol 230-232 ◽  
pp. 1079-1083
Author(s):  
Yi Zhang ◽  
Shi Jie Wang ◽  
Zhong Feng Guo ◽  
Zhong Wei Ren
Keyword(s):  
Friction Coefficient ◽  
Crude Oil ◽  
Constant Temperature ◽  
Testing Machine ◽  
Butadiene Rubber ◽  
Nitrile Butadiene Rubber ◽  
Friction Testing ◽  
Low Load ◽  
Test Result

Select two types of nitrile-butadiene rubber (NBR) which they are different in ingredients, under two types of crude oil medium respectively, the test is carried out on the friction testing machine. The test result shows that under the constant intermediate-low rotate speed and constant temperature, the friction coefficient decreases as the load increases; under the constant intermediate-low load and constant temperature, the friction coefficient increases as the rotate speed increases.

scholarly journals Tribological Properties of Molybdenum Disulfide and Helical Carbon Nanotube Modified Epoxy Resin

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 903 ◽  
Author(s):  
Zhiying Ren ◽  
Yu Yang ◽  
Youxi Lin ◽  
Zhiguang Guo
Keyword(s):  
Elastic Modulus ◽  
Friction Coefficient ◽  
Epoxy Resin ◽  
Molybdenum Disulfide ◽  
Tribological Properties ◽  
Testing Machine ◽  
Three Dimensional ◽  
Friction Testing ◽  
Helical Carbon Nanotubes ◽  
Modified Epoxy

In this study, epoxy resin (EP) composites were prepared by using molybdenum disulfide (MoS2) and helical carbon nanotubes (H-CNTs) as the antifriction and reinforcing phases, respectively. The effects of MoS2 and H-CNTs on the friction coefficient, wear amount, hardness, and elastic modulus of the composites were investigated. The tribological properties of the composites were tested using the UMT-3MT friction testing machine, non-contact three-dimensional surface profilometers, and nanoindenters. The analytical results showed that the friction coefficient of the composites initially decreased and then increased with the increase in the MoS2 content. The friction coefficient was the smallest when the MoS2 content in the EP was 6%, and the wear amount increased gradually. With the increasing content of H-CNTs, the friction coefficient of the composite material did not change significantly, although the wear amount decreased gradually. When the MoS2 and H-CNTs contents were 6% and 4%, respectively, the composite exhibited the minimum friction coefficient and a small amount of wear. Moreover, the addition of H-CNTs significantly enhanced the hardness and elastic modulus of the composites, which could be applied as materials in high-temperature and high-pressure environments where lubricants and greases do not work.

Comparative Study on the Wear Behavior of FPM and NBR in the Natural Crude Oil Medium

2013 ◽  
Vol 456 ◽  
pp. 349-353
Author(s):  
Zhe Wang ◽  
Shi Jie Wang
Keyword(s):  
Friction Coefficient ◽  
Crude Oil ◽  
Wear Behavior ◽  
Testing Machine ◽  
Wear Test ◽  
Premature Failure ◽  
Oil Drilling ◽  
Rotating Speed ◽  
Before And After ◽  
Abrasion Testing

The wear behavior of stator rubber in the natural medium of crude oil in oil-drilling screw pumps directly matters to its service life and sealing property. The premature failure of stator rubber is the main cause for the shortening life of screw pumps. In order to study the wear mechanism of NBR and FPM, a friction wear test was conducted at room temperature by using a MPV-600 micro-computer-controlling grain-abrasion testing machine, in which NBR, FPM and 45# steal pair are the testing subjects. SEM was afterwards employed to observe the surface topography before and after the rubber wear. The test result shows that at the constant low load, the wear extent of FPM increases in a stable, linear way when the rotor rotating speed increases, and the wear extent of NBR increases with the increasing speed of the rotor rotating speed. However, when the rotating speed is over 400r/min, the wear extent of NBR decreases instead. This might be attributed to the improvement of the local lubrication state on the friction surface. Much consistence is indicated in the changing rule of the friction coefficient of the two types of rubber and the changing wear extent with the rotating speed. At the constant, low rotating speed, the wear extent of NBR and FPM basically increases linearly, while the friction coefficient of NBR, FPM and steel pair decreases with the increasing load.

Investigation on Friction and Thermal Expansion Coefficients of Al-Sn Bearing Alloys

2007 ◽  
Vol 353-358 ◽  
pp. 3063-3066 ◽  
Author(s):  
Yong Zhi Zou ◽  
Zheng Bin Xu ◽  
Yan Gao ◽  
Hong Gu ◽  
Jian Min Zeng
Keyword(s):  
Thermal Expansion ◽  
Friction Coefficient ◽  
Testing Machine ◽  
Alloy System ◽  
The Other ◽  
Thermal Expansion Coefficients ◽  
Friction Testing ◽  
Other Hand ◽  
Expansion Coefficients

The influences of Sn addition of 3%-30% on the friction and thermal expansion properties of Al-Sn bearing alloys were investigated in this paper. The experiments were carried out on a specially designed friction testing machine and a dilatometer. It is shown by the experiments that the friction coefficient and hardness of the alloys decrease with the increasing of Sn content. The friction coefficient decreases dramatically when Sn content is higher than 6%. On the other hand, the friction coefficient is also dependent on the load. The friction coefficient increases as the load rises. The linear CTE is also a function of temperature and Sn contents. CTE increases when the temperature rises but has no obvious differences for the alloy system when the temperature is below 80°C. As the temperature rises, the differences become large among the alloy system. The higher the Sn content, the lower the CTE.

The Research on the Lubricating Property of Oil-Air Lubrication in the Sliding Friction Element

2013 ◽  
Vol 572 ◽  
pp. 397-400
Author(s):  
Shao Gang Liu ◽  
Li Quan Li ◽  
Jin Li Wang
Keyword(s):  
Friction Coefficient ◽  
Sliding Friction ◽  
Testing Machine ◽  
Wear Testing ◽  
Conical Nozzle ◽  
Rotating Speed ◽  
Friction Element ◽  
Oil Supply ◽  
Air Supply ◽  
Air Lubrication

The influence of the oil supply, nozzle type, air supply, the performance of sliding friction element under the lubrication preloads were investigated by measuring the element’s temperature and friction coefficient based on the M2000-A friction wear testing machine. When the load, rotating speed and air supply is at 1500N, 210rpm and 2.25 m3/h level respectively, as the oil supply is increased, the temperature rises and friction coefficient decreases. The temperature rise decreases monotonically. The friction coefficient rises monotonically with the air supply increases when the air supply is less than 2.4m3/h, but when the air supply is more than 2.4m3/h, the friction coefficient decreases monotonically. Furthermore, when the oil supply is reached 15ml/h, they remain almost unchanged regardless of direct nozzle and conical nozzle. Nevertheless, the direct nozzle is more suitable than the conical nozzle in oil-air lubrication of the sliding friction pairs .

scholarly journals Theoretical and Experimental Study on the Transient Time-Frequency Characteristics of the Bending-Torsional Coupling Motions of a Rub-Impact Dual-Rotor System

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Tian Gao ◽  
Shuqian Cao ◽  
Tiancheng Zhang
Keyword(s):  
Friction Coefficient ◽  
Fault Detection ◽  
High Speed ◽  
Rotor System ◽  
Bending Vibration ◽  
Transient Time ◽  
Rotating Speed ◽  
Time Frequency ◽  
Runge Kutta Method ◽  
Torsional Coupling

This paper focuses on the fault characteristics of the bending and torsional motions of a rub-impact dual-rotor system caused by aircraft flight maneuvers. The equations of the bending-torsional coupling motion of a dual-rotor system are established considering a low-pressure rotor rub-impact fault and the transient barrel roll flight of an aircraft. The 4th Runge-Kutta method with varied steps is used to obtain the bending and torsional responses. Then, the influences of the system parameters, including the rub-impact stiffness, friction coefficient, and rotating speed, on the bending and torsional motions of the dual-rotor system are investigated in detail. At last, a rotor rubbing experiment is carried out, verifying the validity of the simulation results. The results show that the rub-impact stiffness affects bending vibration significantly and the torsional motion is sensitive to the friction coefficient. Correspondingly, the torsional responses show apparent fractional fault frequencies and rotating fault frequencies within the whole region of the rub-impact stiffness. The bending responses can only display fault frequencies at certain rub-impact stiffness. As for the rotating speed, the torsional responses are also more effective than the bending responses for the rub-impact fault detection at the low- and high-speed regions. The results will contribute to a comprehensive basis for the rub-impact fault detection.

The Study of Blanking Frequency Effect on the Acceleration Performance of Impact Testing Machine Rotor

2014 ◽  
Vol 543-547 ◽  
pp. 150-153
Author(s):  
Yuan Bo Cai ◽  
Fang Zhao ◽  
Shi Jian Li ◽  
Na Zhao
Keyword(s):  
High Speed ◽  
Testing Machine ◽  
Impact Testing ◽  
Frequency Effect ◽  
Rotating Speed ◽  
Impact Testing Machine ◽  
Movement Characteristics ◽  
The Impact ◽  
Feed Inlet

This paper designed an impact testing machine to observe the movement characteristics of particles. We simulated the rotor with different blanking frequency and different rotating speed by EDEM to explore the acceleration of the rotor. Through simulation, blanking frequency could have an impact on the rotor acceleration of testing machine, and the greater Blanking frequency was, the more obvious hanging material phenomenon was. Increasing the diameter of feed inlet could ease the phenomenon of hanging material, but would decrease particles speed. Therefore, we should not only avoid the phenomenon of hanging material, but also make the particles get high speed when designing the impact testing machine.

Influence of Boron Nitride on Tribological Behavior of Nickel-Base Composite Coatings at High Temperature

2011 ◽  
Vol 686 ◽  
pp. 711-715 ◽  
Author(s):  
Yong Kang Zhang ◽  
Jian Liang Li ◽  
Dang Sheng Xiong ◽  
Yong Kun Qin
Keyword(s):  
High Temperature ◽  
Friction Coefficient ◽  
Boron Nitride ◽  
Wear Rate ◽  
Composite Coatings ◽  
Testing Machine ◽  
Optimum Process ◽  
Wear Properties ◽  
Friction Behavior ◽  
Friction Testing

The nickel-based boron nitride composite coatings were prepared by reversing pulse electro-deposition. The mechanical properties and friction behavior of the coatings at high temperature were tested by using Al2O3 ceramic ball at high temperature friction-testing machine. The results show that the surface micro-hardness of the coatings increases with the addition of BN powder. Meanwhile, the friction coefficient and wear rate of specimens decreases. Especially when the BN addition is 1.5g/L the composite coatings present a minimum of friction coefficient and wear rate. In optimum process parameters, the friction coefficient of the coatings is about 0.2 at room temperature and 0.4-0.5 at 600°C. In addition, the friction and wear properties were significantly improved by plating Ni transition layer plated between substrate and composite coating.

Effect of Surface Profile Structure on Stability of Friction and Wear

2004 ◽  
Author(s):  
A. Titov ◽  
R. Dubrovsky
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Testing Machine ◽  
Surface Profile ◽  
Friction Testing ◽  
Test Parameters ◽  
Texture Parameters ◽  
Wear Friction ◽  
Profile Characteristics

This paper describes the role of surface texture parameters of bodies in contact on friction coefficient and wear rate. Experiments are done on wear friction testing machine that allows dynamically tracking friction coefficient and wear rate of surfaces in contact under heavy-duty boundary lubrication conditions. Experiments based on conforming steel 4340 -bronze SAE 40 friction couple showed the role of profile characteristics of bodies in contact such as skewness and bearing length ratio. Experimental results demonstrated that for surfaces with similar roughness, waviness and profile parameters, a surface with skewness higher than −1.3 invokes instability in test parameters causing fast climb of friction coefficient and increased mass loss.

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